There are various types of visual systems which are used with modern vehicular simulators and include motion film projection systems, camera model systems, and digital image generation systems. However, experience has shown that the more acceptable systems used today include camera model systems such as described in U.S. Pat. Nos. 2,975,671; 3,643,345; 3,670,426 and 3,961,133. The other acceptable visual system for todays modern simulators is one that produces a computer generated image such as those systems described in U.S. Pat. Nos. 3,621,214; 3,826,864 and 3,961,133. Although both the camera model systems and the computer image generated systems create or generate their visual scenes by entirely different techniques, both of these systems typically use one or more CRT's (Cathode Ray Tube) for presentation of the desired visual scene. In certain of the systems the CRT's are viewed directly, whereas in other systems the CRT's are viewed by means of optics such as beam splitters and/or mirrors. However, for certain types of applications, it has been found that the scene generated on the CRT may better be viewed in certain simulation situations if the scene is projected onto a large panoramic screen surrounding the simulator or the observer. For these purposes, CRT projectors and laser projector displays are particularly useful. Such projected visual scenes have been found particularly useful in those training situations where the observer is not confined to the interior of the vehicle being simulated. For example, with high performance aircraft it will be appreciated that the pilot is confined to the interior of the cockpit. However, if the vehicle being simulated is, for example, a military tank, a locomotive or an automobile it will be appreciated that at times it might be desirable for the operator to stick his head out of the confines of the cockpit for certain observations even when the vehicle is in operation. This is particularly true in the case of a tank commander that may well want to carefully inspect the surrounding terrain to determine potential dangers, targets and/or direction of travel. Thus, in a real life situation the tank commander may open the tank turret or hatch and take a panoramic observation of the surrounding terrain. Furthermore, in such a situation the tank commander may likely want to closely inspect a portion of the terrain located a substantial distance away by means of hand held binoculars.
Since it is desirable that any training situation be able to closely simulate the real life situation, it will be appreciated that in an effective tank training situation, the commander should be able to use his hand held binoculars to closely inspect a "distant" visual scene. However, if in the training situation a tank commander trainee were to use normal binoculars to closely inspect the visual scene generated by means of a CRT projector or laser projector, there would be little or no further resolution available or information provided by such inspection. That is, real binoculars would magnify the panoramic scene, but still not reveal any further detail. Further, the scene would subjectively appear to be degraded with respect to the scene viewed with a naked eye since magnifying an image with a particular resolution does not increase the resolution of that picture. To use his standard binoculars to gain further information from such a projected scene, it would be necessary that the complete projected scene have significantly greater resolution than is necessary for viewing by the unaided eye or that a small high resolution inset be located in the panoramic display at precisely the location at which the commander is viewing. Unfortunately, such a high resolution picture inset would require a seperate projector having an extensive projection lens so that the inset could be moved to any location which the tank commander might wish to view. It will be appreciated, however, that such an approach is very expensive and difficult to provide. In addition, a sophisticated blanking technique to blank out the low resolution panoramic picture at precisely the correct location so that the inset could be projected instead would be necessary. Such apparatus for a blanking system would, of course, also be very expensive.
Therefore, it is an object of the present invention to provide a simple and inexpensive technique for providing to the eye piece of hand held binoculars a selected scene which is an enlarged and magnified portion of a panoramic scene.
It is still another object of this invention to provide a method and apparatus for inspecting a portion of a panoramic scene without having to blank out a portion of the panoramic scene and inset a high resolution scene.
It is yet another object of the present invention to provide a method and apparatus for closely inspecting a portion of a panoramic scene by means of hand held binoculars without having to provide increased resolution of the panoramic scene.
A particular type of visual system for extremely wide angle viewing is disclosed in U.S. Pat. No. 4,048,653. This particular technique is a projection technique which uses the pilot's helmet as part of the lens and projection system. Except for the fact that a portion of the visual system is in close proximity with the observers eyes such as would be the case with a periscope or set of binoculars, there is no similarity between the technique described in this patent and the present invention.